Field-induced enhancements of dielectronic recombination in Na-like S and Ar

We present first storage ring measurements of dielectronic recombination in the presence of external electric fields for for astrophysically abundant Na-like S5+ and Ar7+ ions. Enhancement factors of over 2 and 1.8 were found in case of Na-like S and Na-like Ar, respectively. And, even higher enhancements are to be expected at stronger fields.